개인화 코디 추천을 위한 위음성 증류 및 대조 학습

학위논문(석사) -- 서울대학교대학원 : 공과대학 컴퓨터공학부, 2022.2. 이상구.Personalized outfit recommendation has recently been in the spotlight with the rapid growth of the online fashion industry. However, recommending outfits has two significant challenges that should be addressed. The first challenge is that outfit recommendation often requires a complex and large model that utilizes visual information, incurring huge memory and time costs. One natural way to mitigate this problem is to compress such a cumbersome model with knowledge distillation (KD) techniques that leverage knowledge from a pretrained teacher model. However, it is hard to apply existing KD approaches in recommender systems (RS) to the outfit recommendation because they require the ranking of all possible outfits while the number of outfits grows exponentially to the number of consisting clothing items. Therefore, we propose a new KD framework for outfit recommendation, called False Negative Distillation (FND), which exploits false-negative information from the teacher model while not requiring the ranking of all candidates. The second challenge is that the explosive number of outfit candidates amplifying the data sparsity problem, often leading to poor outfit representation. To tackle this issue, inspired by the recent success of contrastive learning (CL), we introduce a CL framework for outfit representation learning with two proposed data augmentation methods. Quantitative and qualitative experiments on outfit recommendation datasets demonstrate the effectiveness and soundness of our proposed methods.최근 온라인 패션 산업이 급성장하면서 개인화 코디 추천이 각광받고 있다. 그러나 코디 추천은 해결해야 할 두 가지 중요한 챌린지가 있다. 첫 번째 챌린지는 코디 추천이 주로 시각 정보를 활용하는 복잡하고 큰 모델을 필요로 하기 때문에 상당한 시간과 메모리 비용이 발생한다는 것이다. 이 문제를 완화하는 한 가지 자연스러운 방법은 사전 훈련된 교사 모델의 지식을 활용하는 지식 증류 기술을 이용하여 이러한 성가신 모델을 압축하는 것이다. 그러나 추천 시스템의 기존 지식 증류 접근법은 가능한 모든 코디의 순위를 필요로 하며, 코디의 수는 구성되는 의상의 수에 따라 기하급수적으로 증가하기 때문에 코디 추천에 기존 지식 증류 접근법을 적용하는 것은 상당히 까다로운 작업이다. 따라서 우리는 모든 후보 코디의 순위를 요구하지 않으면서 교사 모델의 위음성 정보를 활용하는 위음성 증류라는 새로운 지식 증류 프레임워크를 제안한다. 두 번째 챌린지는 코디 후보의 폭발적인 수로 인해 데이터 희소성 문제가 증폭되어 종종 코디 표현(representation)이 좋지 않다는 것이다. 이 문제를 해결하기 위해 최근 대조 학습의 성공에 영감을 받아 새로운 두 가지 데이터 증강 기법을 사용하는 코디 표현 학습을 위한 대조 학습 프레임워크를 제안한다. 우리는 코디 추천 데이터 세트에 대한 양적 및 질적 실험을 통해 제안된 방법의 효과와 타당성을 보인다.Abstract i Contents ii List of Tables v List of Figures vi 1 Introduction 1 2 Related Work 5 2.1 Outfit Recommendation 5 2.2 Knowledge Distillation 6 2.3 Contrastive Learning 6 3 Approach 7 3.1 Background: Computing the Preference Score to an Outfit 8 3.1.1 Set Transformer 9 3.1.2 Preference score prediction 10 3.2 False Negative Distillation 10 3.2.1 Teacher model 10 3.2.2 Student model 11 3.3 Contrastive Learning for Outfits 13 3.3.1 Erase 14 3.3.2 Replace 14 3.4 Final Objective: FND-CL 14 3.5 Profiling Cold Starters 15 3.5.1 Average (avg) 16 3.5.2 Weighted Average (w-avg) 16 4 Experiment 17 4.1 Experimental Design 17 4.1.1 Datasets 17 4.1.2 Evaluation metrics 18 4.1.3 Considered methods 18 4.1.4 Implementation details 19 4.2 Performance Comparison 20 4.3 Performance on Cold Starters 21 4.4 Performance on Hard Negative Outfits 22 4.5 Performance with Different α 23 4.6 Performance with Different Augmentations 24 4.7 Performance with Different Model Sizes 25 4.8 Performance with Different Batch Sizes 27 4.9 Visualization of the User-Outfit Space 28 5 Conclusion 30 Bibliography 31 A Appendix 37 A.1 Enhancing the Performance of a Teacher Model 37 A.1.1 Teacher-CL 38 A.1.2 Employing Teacher-CL: FND-CL* 39 Abstract (In Korean) 40석

사람 코로나바이러스 (SARS-CoV-2)와 돼지 코로나바이러스 (PEDV)의 유전학적 분석과 유전적 변이가 바이러스 항원성과 진단에 영향을 미칠 가능성

학위논문 (박사) -- 서울대학교 대학원 : 수의과대학 수의학과, 2021. 2. 박용호.바이러스는 면역 회피를 유발할 수 있는 유전적 돌연변이를 통해 숙주 면역과 계속해서 싸우고 있으며, 이러한 바이러스의 생존 전략은 앞으로도 계속 될 것이다. 특히, 유전자 변이에 따른 아미노산 서열의 비상동성 (non-synonymous) 변화는 바이러스 에피톱의 항원성을 변화시킬 수 있으며, 이러한 변화는 기존에 개발된 백신의 방어능을 저하시킬 수 있다. 또한, 바이러스의 염기서열의 변이는 현재 일상적으로 사용되는 진단 기술인 중합효소연쇄반응 (PCR)과 효소결합면역흡착분석법 (ELISA)의 진단 정확도를 저해 할 수 있다. 따라서 바이러스가 진화함에 따른 중요한 그들의 유전학적 변화를 조사하고 추적하는 것은 바이러스에 대한 적절한 예방 및 진단 전략을 수립하는 데 매우 큰 도움이 된다. 이 연구에서는 현재 사람과 돼지에서 심각한 문제가 되고 있는 코로나바이러스의 유전적 변이와 그 변이들이 바이러스의 항원성과 진단에 영향을 미칠 가능성에 대해 조사하였다. 첫 번째 장에서는 최근 사람에서 문제가 되고 있는 severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)를 분석하였다. 코로나바이러스의 스파이크 (S) 단백질은 바이러스의 세포 내 유입에 결정적인 역할을 하는 표면 단백질이다. 따라서, 이 연구에서는 항원성과 면역학적 특징을 확인하기 위해 SARS-CoV-2의 S 유전자를 분석하였다. S 유전자를 기반으로 한 계통학적 분석에서 SARS-CoV-2 분리주들 사이에 두 개의 유전자 그룹이 존재하는 것을 확인하였다. 이 두 개의 유전자 그룹은 하나의 특이적인 염기서열 변이인 D614G에 의해 나뉘었다. 이 변이는 SARS-CoV-2가 숙주의 면역체계를 회피하는데 결정적인 역할을 할 것으로 생각되었다. D614G 염기서열 변이를 포함하는 S1 domain의 에피톱 부위에 대해 항원 지수 분석을 시행한 결과, SARS-CoV-2b 유전자 그룹이 SARS-CoV-2a 유전자 그룹에 비해 유의적으로 감소한 항원 지수를 보이는 것으로 확인하였다. 따라서, 이 유전적 변이에 의해 두 유전자 그룹간의 항원성 차이가 발생하였을 것으로 생각되었다. 두 유전자 그룹간 항원성 차이가 발생하였다면 두 유전자 그룹을 백신에 포함시키는 것이 COVID-19을 방어하는데 보다 효율적일 것이다. 그러므로, 실제로 두 유전자 그룹간 항원성 차이가 발생하였는지 확인하는 것이 시급하다. 두 번째 장에서는 전 세계 돼지 산업에 지속적이고 심각한 피해를 입히고 있는 돼지유행성설사바이러스 (PEDV)를 분석하였다. 최근 양돈장의 PEDV 유병률은 약 9.92 %로 지속적으로 문제가 되고 있음이 확인되었다. 뉴클레오캡시드 (N) 유전자를 기반으로 베이지안 계통 분석을 진행한 결과, 세 개의 주요 N 유전자 기반 유전자 그룹 (N1, N2 및 N3)과 두 개의 하위 유전자 그룹 (N3a과 N3b) 을 확인하였다. N 단백질에 포함된 에피톱 부분의 항원 지수를 분석한 결과, 유전자 그룹간 항원성에 차이가 있을 것으로 강하게 의심되었다. 에피톱 부위에서 N3 유전자 그룹의 항원 지수는 N1 및 N2 유전자 그룹의 항원 지수에 비해 유의하게 낮았다. 이러한 변화는 N1 단백질을 항원으로 사용하는 ELISA 키트의 진단 결과에 영향을 미칠 것으로 판단되었다. 또한, 최근 확인된 한국 PED 바이러스들의 S 유전자를 분석한 결과, 스파이크 단백질 (COE, S1D 및 2C10)의 B 세포 에피토프 서열의 일부에서 유의적으로 낮은 항원 지수가 확인되었다. 이러한 S 및 N 유전자의 면역학적 주요 부위에 유전적 변이가 발생한 PED 바이러스들은 기존에 확립된 숙주 면역을 회피하여 돼지 농장에 심각한 손상을 줄 수 있기 때문에 지속적인 감시가 필요하다. 이 연구에서 바이러스의 면역 회피나 진단 오류를 유발할 수 있는 중요한 유전적 변이를 현재 심각한 문제가 되고 있는 사람과 돼지 코로나바이러스에서 확인하였다. 이러한 발견은 바이러스 감염 예방에 대한 더 나은 이해와 보다 정확한 진단법을 개발하는데 도움을 줄 것으로 기대한다. 나아가 향후 코로나바이러스 진화에 적절히 대응할 수 있도록 유전자 분석을 통한 지속적인 감시가 유지되어야 한다.Aspect of virus evolution, viruses have continued to fight with host immune through genetic mutation facilitating immune evasion and this strategy of viruses for their survival will continue in the future. Genetic mutation, which may change structural form of viral proteins by non-synonymous changes, may alter antigenicity of a viral epitope and in turn can lead to decreased efficacy of previously developed vaccine for the virus. Furthermore, such genetic mutation can hamper diagnostic accuracy of polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), which are routinely used diagnostic techniques. Thus, it is very important work to investigate and track critical genetic events along with virus evolution. These efforts can give worthy information and insight to establish appropriate prevent and diagnostic strategy for viruses. Herein, human and animal coronaviruses causing sever disease were investigated by genetic and phylogenetic analysis. As stated in chapter I, The S glycoprotein of coronaviruses is important for viral entry and pathogenesis with most variable sequences. Therefore, we analyzed the S gene sequences of SARS-CoV-2 to better understand the antigenicity and immunogenicity of this virus in this study. In phylogenetic analysis, two subtypes (SARS-CoV-2a and -b) were confirmed within SARS-CoV-2 strains. These two subtypes were divided by a novel non-synonymous mutation of D614G. This may play a crucial role in the evolution of SARS-CoV-2 to evade the host immune system. The region containing this mutation point was confirmed as a B-cell epitope located in the S1 domain, and SARS-CoV-2b strains exhibited severe reduced antigenic indexes compared to SARS-CoV-2a in this area. This may allow these two subtypes to have different antigenicity. If the two subtypes have different serological characteristics, a vaccine for both subtypes will be more effective to prevent COVID-19. Thus, further study is urgently required to confirm the antigenicity of these two subtypes. As stated in chapter I, Porcine epidemic diarrhea virus (PEDV) causes continuous, significant damage to the swine industry worldwide. By RT-PCR-based methods, this study demonstrated the ongoing presence of PEDV in pigs of all ages in Korea at the average detection rate of 9.92%. By the application of Bayesian phylogenetic analysis, it was found that the nucleocapsid (N) gene of PEDV could evolve at similar rates to the spike (S) gene at the order of 10−4 substitutions/site/year. Based on branching patterns of PEDV strains, three main N gene-based genogroups (N1, N2, and N3) and two sub-genogroups (N3a, N3b) were proposed in this study. By analyzing the antigenic index, possible antigenic differences also emerged in both the spike and nucleocapsid proteins between the three genogroups. The antigenic indexes of genogroup N3 strains were significantly lower compared with those of genogroups N1 and N2 strains in the B-cell epitope of the nucleocapsid protein. Indeed, there is different antigenicity between the genogroups based on the N gene, it may affect diagnostic results using commercial ELISA kits based on N1 protein. Similarly, significantly lower antigenic indexes in some parts of the B-cell epitope sequences of the spike protein (COE, S1D, and 2C10) were also identified. PEDV mutants derived from genetic mutations of the S and N genes may cause severe damage to swine farms by evading established host immunities. In conclusion, the crucial genetic variations, which may induce immune evasion or diagnostic error, were revealed in these coronavirus. It is expected that these results provide better understanding for preventing viral infection and more precise diagnosis. Also, constant surveillances through genetic analysis should maintain to appropriately respond to coronavirus evolution in the future.Abstract iv List of Figures ix List of Tables x General introduction 11 Literature review 14 1. Coronavirus 15 1.1. General overveiw 17 1.2. SARS-CoV-2: Human betacoronavirus 17 1.3. Porcine epidemic diarrhea virus: Animal alphacoronavirus 19 2. Virus evolution and genetic analysis on viruses 23 2.1. Antigenic drift and genetic shift 23 2.2. Genetic mutation and recombination 23 2.3. Mutation rate of DNA and RNA viruses 25 2.4. Phenotypic Variation by Mutations 26 2.5. Phylogenetic analysis on viruses 26 3. Impact of genetic mutation on viral antigenicity and diagnosis 28 Chapter I 31 Abstract 32 1. Introduction 33 2. Material and Methods 34 2.1. Sample collection and Phylogenetic analysis 34 2.2. Epitope prediction and antigenic index analysis on S gene sequences 34 3. Results 35 3.1. Phylogenetic analysis on S gene of SARS-CoV-2 35 3.2. Epitope prediction of S protein 35 3.3. Antigenic index analysis on the epitope of S1 subunit 35 4. Discussion 36  Chapter II 43 Abstract 44 1. Introduction 45 2. Materials and Methods 47 2.1. Sample collection, PEDV detection by PCR, and complete sequencing 47 2.2. Genetic analysis of recombination 48 2.3. Bayesian phylogenetic analysis 50 2.4. Pairwise genetic distance (p-Distance) analysis 51 2.5. Inferring ancestral amino acid changes 51 2.6. Amino acids and antigenic index analysis of N gene 51 2.7. Antigenic index analysis of B-cell epitopes in Korean PEDV strains 52 3. RESULTS 53 3.1. The detection of PEDV in Korea from 2017 to 2018 53 3.2. Phylogenetic analysis of global PEDV strains 56 3.3. Evolutionary rates of PEDV genes 60 3.4. Amino acids and antigenic index analysis of N gene sequences 60 3.5. Antigenic index analysis of S protein B-cell epitopes in Korean PEDV strains 61 4. Discussion 66 General conclusions 69 References 71 국문 초록 88Docto

Intra-articular Avulsion Fractures of the Malleolus in Chronic Ankle Pain

Purpose: We report our results of arthroscopic treatment of symptomatic avulsion fracture of the malleolus in chronic ankle pain, and also analyzed the clinical and radiological features for evaluating the good candidate for arthroscopic treatment. Material and Methods: Fourteen patients who were diagnosed with intra-articular avulsion fractures of the malleolus received arthroscopic surgery and were followed up for at least a year. The clinical and radiological characters including MRI and arthroscopic findings were reviewed. Clinical assessments were done according to the AOFAS score system. Results: There was a history of inversion type of the injury in most cases and local tenderness of lesion site was a unique. MRI study showed thickened anterior talofibular ligament (ATFL) in 8 cases (57%) and discontinued ATFL in 3 cases (21%). Enhanced signal surrounding soft tissue corresponding to synovial inflammation and impingement was found in 12 cases (86%). Preoperative score of all patients were 74.0±5.5, which improved to 89.3±6.7 at the follow-up after the treatment (P<0.001). Conclusions: Most patients had history of injury and localized tenderness in the area coinciding with radiological findings. Thickened ATFL and contrast enhancement around the ossicle were frequently found. Symptomatic avulsion fractures of the malleolus associated with the clinical and radiological findings above could be a good candidate for arthroscopic treatment.ope

Peroxisome Proliferator-Activated Receptor γ Activation Promotes Adipogenesis in Human Mesenchymal Stem Cells

Purpose: In this study, we determined that the troglitazones could induce uniform adipogenesis of human mesenchymal stem cells (MSCs) within a short time in a dose- and a time-dependent manners. Materials and Methods: Human MSCs were isolated from bone marrow and cultured in basal or adipogenic medium in the presence of 0 50 μM troglitazone for 5 days. Then we performed flow cytometry, RT-PCR and western blot analysis. Results: In FACS assay, troglitazone induced adipocyte differentiation in a dose-dependent manner. At concentration of 25 μM troglitazone in adipogenic medium, over 50% of the cells differentiated into adipocytes at day 5. This was accompanied by increased mRNA levels for the adipocyte gene markers (LPL, aP2 and PPARγ) in RT-PCR. In western blot analysis, we found that ERK phosphorylation was inhibited in the early stage of adipogenesis. Conclusion: Through the addition of troglitazone as a PPAR γ agonist, we could get the uniform adipogenic differentiation within a short time. Thus, troglitazone directly regulates differentiation of human MSCs into adipocytes; induced PPAR γ expression may play a key regulatory role in this process. And we suggest a role for ERK as a regulatory switch for these differentiation pathwaysope

중심체 단백질인 CEP215 의 세포주기에 따른 기능 연구

학위논문 (박사)-- 서울대학교 대학원 : 생명과학부, 2014. 2. 이건수.In most animal cells, the centrosome functions as a major microtubule organizing center and controls cellular morphology, migration, subcellular transport and cell division. Understanding the functional mechanisms of this mysterious and interesting organelle at the molecular level has been a great topic in molecular and cellular biology. Meanwhile, proteomic analysis revealed that human centrosome is composed of several hundred kinds of proteins. The composition of the centrosome changes dynamically during the cell cycle. Among the centrosomal proteins, I focused on the functional mechanisms of CEP215, an important pericentriolar material component, for microtubule nucleation and centrosome maturation during interphase and mitosis, respectively. In chapter 1, I investigated the knockdown phenotypes of CEP215 during interphase. It has been reported that CEP215 is involved in several centrosome behaviors such as centrosome cohesion, microtubule nucleation and centrosome maturation. However, the precise mechanisms of these functions have not been thoroughly explored. Thus, I focused on biological roles of CEP215 for microtubule nucleation in interphase. The results revealed that the physical interaction of CEP215 with γ-tubulin is essential for the microtubule nucleation in interphase cells. In chapter 2, I investigated roles of CEP215 in mitotic cells. From chapter 1, I found that CEP215 physically interacts with γ-tubulin in interphase cells. Here, I hypothesized that the interaction of CEP215 with γ-tubulin also contributes to the centrosome maturation during mitosis. It was unexpected that the physical interaction of CEP215 with γ-tubulin is not necessary for the centrosome maturation. Rather, physical interaction of CEP215 with pericentrin is critical for the centrosome maturation and subsequent proper bipolar spindle formation during mitosis. The present results provide an insight into how pericentriolar material components are assembled to form a spindle pole during mitosis.Docto

Risk factors for medial meniscus posterior root tear

BACKGROUND: Medial meniscus posterior root tears (MMPRT) have a different clinical effect from other types of meniscal tears. These tears are very common among Asian people and may be related to the frequent use of postures such as the lotus position or squatting. PURPOSE: The present study was designed to identify the risk factors for MMPRT among an Asian sample. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: An observational study was performed of 476 consecutive patients undergoing an arthroscopic procedure on their medial meniscus from January 2010 to December 2010. One hundred four patients had MMPRT (group 1), and the other patients had other types of medial meniscal tears (group 2). Demographic characteristics (age, sex, body mass index [BMI]), radiographic features (mechanical axis angle, tibia vara angle, tibial slope angle, Kellgren-Lawrence grade [KLG]), and environmental factors (occupation, trauma history, sports activity level, table use or not, bed use or not-variables that are representative of the oriental lifestyle of lotus position and squatting) were surveyed. We assessed the relation of these risk factors to the type of meniscal tear (group 1 or 2). RESULTS: In group 1, there were 7 male and 97 female patients, with an average age of 58.2 years (range, 39-78 years) and BMI of 26.7 ± 3.4 kg/m2. In group 2, there were 136 male and 236 female patients (P < .01 compared with group 1), with an average age of 54.3 years (range, 17-77 years; P < .01) and a BMI of 24.9 ± 3.1 kg/m2 (P < .01). With regard to radiographic features, the mechanical axis angle demonstrated a significantly increased varus alignment in group 1 (4.5° ± 3.4°) compared with group 2 (2.4° ± 2.7°; P < .01), and the KLG was 1.4 ± 0.8 in group 1 and 0.9 ± 0.6 in group 2 (P < .01). Environmental factors showed no differences in occupation, table use or not, and bed use or not, except sports activity level. There were 41 patients (42.7%) in group 1 and 77 patients (20.6%) in group 2 who did not participate in any recreational activity (P < .01). Multiple logistic regression analysis showed that female sex was associated with a 5.9-fold increase in risk (95% confidence interval [CI], 2.138-16.575), a varus mechanical axis angle with a 3.3-fold increase (95% CI, 1.492-7.153), a BMI more than 30 kg/m2 with a 4.9-fold increase (95% CI, 1.160-20.955), and lower sports activity level with a 2.7-fold increase (95% CI, 1.011-7.163) for MMPRT. CONCLUSION: Persons with MMPRT had significantly increased age, female sex predominance, higher BMI, increased KLG, greater varus mechanical axis angle, and lower sports activity level compared with persons with other types of meniscal tear. After adjusting for other factors, sex, BMI, mechanical axis angle, and lower sports activity level remained strong determinants of MMPRT. Interestingly, oriental postural positions including the lotus position and squatting showed no contribution to increased risk of MMPRT. This suggests that intrinsic risk factors (similar to those that predispose to osteoarthritis) predispose to MMPRT.ope

Arthroscopic Repair of Type II SLAP Lesion with Bioabsorbable Knotless Suture Anchor: Surgical Technique and Clinical Results

Purpose: The purpose of this study was to evaluate the results of bioabsorbable knotless suture anchoring for isolated type II SLAP.0aMaterials and Methods: Fourteen patients with isolated type II SLAP underwent a surgical repair with bioabsorbable knotless anchor arthroscopically. Instability, rotator cuff tears or simple subacromial decompression were excluded. The UCLA and pain of VAS (Visual Analogue Scale), ADL (Activity of Daily Living, from the American Shoulder and Elbow Society) were evaluated and patients underwent a thorough shoulder examination at a minimum follow-up period of 2 years postoperatively.0aResults: At a mean of 27.1 months follow-up. The mean UCLA score improved from 14.4 pre-operatively to 31.2 on last follow-up. The mean VAS for pain was 4.9 and on last follow-up 1.0. The mean VAS for instability was 2.6 and on last follow-up 0.5. The mean ADL was 10.4 and on last follow-up 25.0. 12 patients reported their satisfaction as good to excellent and 10 of the 14 patients returned to their pre-injury level of activity (athletics) (P<0.05).0aConclusion: Arthroscopic repair with bioabsorbable knotless suture anchors is an effective surgical technique for the treatment of an isolated unstable type II SLAP lesion. Overall satisfaction was only 85.7%. 1 patient had severe stiffness and 1 patient had shoulder pain.ope

Arthroscopic Partial Repair of Massive Contracted Rotator Cuff Tears

Typically, massive rotator cuff tears have stiff and retracted tendon with poor muscle quality, in such cases orthopaedic surgeons are confronted with big challenging to restore the cuff to its native footprint. Furthermore, even with some restoration of the footprint, it is related with a high re-tear rate due to less tension free repair and less tendon coverage. In this tough circumstance, the partial repair has yielded satisfactory outcomes at relatively short follow-up by re-creating the transverse force couple of the rotator cuff. Through this partial repair, the massive rotator cuff tear can be converted to the "functional rotator cuff tear" and provide improvement in pain and functional outcomes in patient's shoulder.ope

Biomechanical evaluation of the influence of posterolateral corner structures on cruciate ligaments forces during simulated gait and squatting

Posterolateral corner (PLC) structures of the knee joint comprise complex anatomical soft tissues that support static and dynamic functional movements of the knee. Most previous studies analyzed posterolateral stability in vitro under static loading conditions. This study aimed to evaluate the contributions of the lateral (fibular) collateral ligament (LCL), popliteofibular ligament (PFL), and popliteus tendon (PT) to cruciate ligament forces under simulated dynamic loading conditions by using selective individual resection. We combined medical imaging and motion capture of healthy subjects (four males and one female) to develop subject-specific knee models that simulated the 12 degrees of freedom of tibiofemoral and patellofemoral joint behaviors. These computational models were validated by comparing electromyographic (EMG) data with muscle activation data and were based on previous experimental studies. A rigid multi-body dynamics simulation using a lower extremity musculoskeletal model was performed to incorporate intact and selective resection of ligaments, based on a novel force-dependent kinematics method, during gait (walking) and squatting. Deficiency of the PLC structures resulted in increased loading on the posterior cruciate ligament and anterior cruciate ligament. Among PLC structures, the PT is the most influential on cruciate ligament forces under dynamic loading conditions.ope

Treatment of Open Proximal Humerus Fracture by Gunshot.

PURPOSE: To consider the proper managment of proximal humerus fracture on gunshot wounds. MATERIALS AND METHODS: A 28-year-old male patient, who sustained a gunshot injury on the left arm 5 days ago, was admitted through the emergency department. Although he underwent an emergency surgery (bullet fragment removal and debridement), there remained bullet fragments around the proximal humerus fracture site. The wound seemed to be infected and a partial dehiscence occurred. No neurologic deficit was noted. Immediate exploration and debridement were performed, and an external fixator was applied to restore the anatomical alignment and manage the wounds. Intravenous antibiotics were administered. On the 9th postoperative day, wound debridement was done again, and cement beads mixed with antibiotics were inserted. After two weeks, the external fixator was removed, and the pin sites were closed after debridement. One week later, the open reduction and internal fixation with locking compression plate and screws were done. RESULTS: At 3 months after the internal fixation, the bone union was obtained with satisfactory alignment of the humerus. CONCLUSION: The severity of the soft tissue injury influences the fracture management plan. Further, the risk on lead toxicity should be considered.ope